If you roll one die you get 1-6 equally. If you roll two dice you get 7 most often, 6 and 8 slightly less, 5 and 9 even less, etc. Say you only have 1 die and

If you roll one die you get 1-6 equally. If you roll two dice you get 7 most often, 6 and 8 slightly less, 5 and 9 even less, etc. Say you only have 1 die and want to generate the random number distribution that 2 dice give. Easy, just roll twice, and add them. But what if you only have the output from 2 dice, and want to pretend to roll 1 die. You need a more general way of converting one random distribution to another.